How to store pressurized gas cylinders safely

On June 24, 2005, fire and explosions swept through the Praxair Distribution, Inc., gas cylinder filling and distribution center in St. Louis, Missouri. The accident occurred when gas released by a pressure relief valve on a propylene cylinder ignited.

The U.S. Chemical Safety Board (CSB) investigators noted the accident occurred on a hot summer day with a high temperature of 97 degrees F in St. Louis. At Praxair, cylinders were stored in the open on asphalt, which radiated heat from the direct sunlight, raising the temperatures and pressure of the gas inside the cylinders. At approximately 3:20 p.m., a propylene cylinder pressure relief valve began venting. CSB investigators believe static electricity, created by escaping vapor and liquid, most likely ignited the leaking propylene.

The CSB issued Safety Bulletin listing several best practices for cylinder storage at gas repackaging facilities, including fire protection systems to cool cylinders and limit the spreading of fires, adding barriers to contain exploding propylene cylinders within the facility, and gas detection systems that can sound alarms and activate fire mitigation systems.

The following video shows the initial fire spreading quickly to other cylinders. Exploding cylinders – mostly acetylene – flew up to 800 feet away, damaged property, and started fires in the community. The fire could not be extinguished until most of the flammable gas cylinders were expended. An estimated 8,000 cylinders were destroyed in the fire, which took five hours to control.